Sphere-Shaped Lost Circulation Material (LCM) Having Hooks and Latches

ABSTRACT

A lost circulation material (LCM) that includes spheres having radially distributed hooks and latches to facilitate engagement (such as interlocking) of the spheres is provided. Each sphere has a plurality of hooks and a plurality of latches to engage latches and hooks respectively of adjacent spheres. Each hook may include two hook arms, and each latch may define an aperture to receive a hook arm. The spheres may form plugs in channels, fractures, and other openings in a lost circulation zone. Additionally or alternatively, the spheres may form a bridge on which other LCMs may accumulate to seal openings in a lost circulation zone. Methods of preventing lost circulation using the spheres are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority from U.S.Non-provisional application Ser. No. 16/561,927 filed Sep. 5, 2019, andtitled “SPHERE-SHAPED LOST CIRCULATION MATERIAL (LCM) HAVING HOOKS ANDLATCHES,” a copy of which is incorporated by reference in its entiretyfor purposes of United States patent practice.

BACKGROUND Field of the Disclosure

The present disclosure generally relates to controlling lost circulationin a wellbore during drilling with a drilling fluid. More specifically,embodiments of the disclosure relate to a lost circulation material(LCM).

Description of the Related Art

Lost circulation is one of the frequent challenges encountered duringdrilling operations. Lost circulation can be encountered during anystage of operations and occurs when drilling fluid (such as drillingmud) pumped into a well returns partially or does not return to thesurface. While some fluid loss is expected, excessive fluid loss is notdesirable from a safety, an economical, or an environmental point ofview. Lost circulation is associated with problems with well control,borehole instability, pipe sticking, unsuccessful production tests, poorhydrocarbon production after well completion, and formation damage dueto plugging of pores and pore throats by mud particles. In extremecases, lost circulation problems may force abandonment of a well.

Lost circulation can occur in various formations, such as naturallyfractured formations, cavernous formations, and highly permeableformations (for example, “super-K” formations having a permeabilitygreater than 500 millidarcy). Lost circulation can be categorized by theamount of fluid or mud lost as seepage type, moderate type, severe type,and total loss. The extent of the fluid loss and the ability to controlthe lost circulation with an LCM depends on the type of formation inwhich the lost circulation occurs.

SUMMARY

Lost circulation materials (LCMs), also referred to as loss controlmaterials are used to mitigate the lost circulation by blocking the pathof the drilling fluid (such as drilling mud) into the formation. Manyexisting LCMs include naturally-occurring or shaped materials that mayhave spherical, fibrous, or flaky shapes to block fractures, channels,and other openings in lost circulation zones. However,naturally-occurring or shaped materials may not have the optimal shapesfor forming bridges or plugs in fractures, channels, and other openingsin lost circulation zones to achieve a desired lost circulationperformance.

Additionally, naturally-occurring or shaped materials may also sufferfrom insufficient mechanical strength, chemical resistance, thermalstability, and biological degradation. Consequently, existing LCMsformed from naturally-occurring or shaped materials may perform poorlyat downhole conditions and may not seal and block lost circulation zonesfor sufficient time periods.

Many naturally-occurring or shaped LCMs swell in exposure to liquids ina well. However, swellable LCMs may have various problems, including arisk of premature swelling which could plug a bottom hole assembly(BHA), drill pipe, or both. Swellable LCMs may also have a risk of lateswelling such that an LCM is ineffective and does not swell in the lostcirculation zone and is swept away before use.

Embodiments of the disclosure are directed to an LCM having a pluralityof spheres such that each sphere has a plurality of radially distributedhooks and latches to facilitate engagement (such as interlocking) of thespheres. Advantageously, the spheres do not rely on swelling to formplugs or bridges in a lost circulation zone. The spheres may formimproved and more effective plugs as compared to natural LCM products.Further, the spheres may form bridges in the lost circulation zone toenable the accumulation of an additional LCM for improved sealing of thelost circulation zone.

In one embodiment, a method to control lost circulation in a lostcirculation zone in a wellbore is provided. The method includesintroducing an altered carrier fluid into the wellbore such that thealtered carrier fluid contacts the lost circulation zone, such that thealtered carrier fluid includes a carrier fluid and a lost circulationmaterial (LCM). The LCM includes a plurality of spheres. Each sphereincludes a sphere body and a plurality of hooks, each hook extendingoutward from a surface of the sphere body and having a first hook armand a second hook arm, the second hook arm extending in a directionopposite the first hook arm. Each sphere also includes a plurality oflatches, each latch extending outward from the surface of the spherebody and having an aperture. A hook of a sphere of the plurality ofspheres is configured to engage a latch of an adjacent sphere viainsertion of a first hook arm or a second hook arm through the aperturesuch that the plurality of spheres form a structure.

In some embodiments, the LCM consists of the plurality of spheres. Insome embodiments, the carrier fluid is an oil-based drilling mud or awater-based drilling mud. In some embodiments, the LCM is a first LCM,such that the method includes introducing an altered drilling fluid intothe wellbore such that the altered drilling fluid contacts the lostcirculation zone and the altered drilling fluid includes a drillingfluid and a second LCM, such that the second LCM accumulates on thestructure. In some embodiments, each sphere of the plurality of sphereshas a diameter in the range of 5 millimeter to 38 mm. In someembodiments, the sphere body has a diameter in the range of 3millimeters to 34 mm. In some embodiments, the plurality of hooks andthe plurality of latches have an alternating pattern. In someembodiments, each hook of the plurality of hooks is separated from anadjacent latch of the plurality of latches by a radial distance in therange of 10° to 45°. In some embodiments, each hook of the plurality ofhooks has a length and the sphere body has a diameter, such that theratio of the length to the diameter is in the range of 0.1 to 3.5. Insome embodiments, each latch of the plurality of latches has a lengthand the sphere body has a diameter, such that the ratio of the length tothe diameter is in the range of 0.1 to 3.5. In some embodiments,introducing the altered carrier fluid into the wellbore includes pumpingthe altered carrier fluid through a drill bit. In some embodiments,introducing the altered carrier fluid into the wellbore includes using abypass system. In some embodiments, introducing the altered carrierfluid into the wellbore includes introducing the altered carrier fluidinto the wellbore using an open-ended drill pipe.

In another embodiment, a lost circulation material (LCM) composition isprovided. The LCM includes a plurality of spheres. Each sphere includesa sphere body and a plurality of hooks, each hook extending outward froma surface of the sphere body and having a first hook arm and a secondhook arm, the second hook arm extending in a direction opposite thefirst hook arm. Each sphere also includes a plurality of latches, eachlatch extending outward from the surface of the sphere body and havingan aperture. A hook of a sphere of the plurality of spheres isconfigured to engage a latch of an adjacent sphere via insertion of afirst hook arm or a second hook arm through the aperture such that theplurality of spheres form a structure.

In some embodiments, each sphere of the plurality of spheres has adiameter in the range of 5 millimeter to 38 mm. In some embodiments, thesphere body has a diameter in the range of 3 millimeters to 34 mm. Insome embodiments, the plurality of hooks and the plurality of latcheshave an alternating pattern. In some embodiments, each hook of theplurality of hooks is separated from an adjacent latch of the pluralityof latches by a radial distance in the range of 10° to 45°. In someembodiments, each hook of the plurality of hooks has a length and thesphere body has a diameter, such that the ratio of the length to thediameter is in the range of 0.1 to 3.5. In some embodiments, each latchof the plurality of latches has a length and the sphere body has adiameter, such that the ratio of the length to the diameter is in therange of 0.1 to 3.5.

In another embodiment, an altered drilling fluid is provided. Thealtered drilling fluid includes a drilling fluid and a plurality ofspheres. Each sphere includes a sphere body and a plurality of hooks,each hook extending outward from a surface of the sphere body and havinga first hook arm and a second hook arm, the second hook arm extending ina direction opposite the first hook arm. Each sphere also includes aplurality of latches, each latch extending outward from the surface ofthe sphere body and having an aperture. A hook of a sphere of theplurality of spheres is configured to engage a latch of an adjacentsphere via insertion of a first hook arm or a second hook arm throughthe aperture such that the plurality of spheres form a structure.

In some embodiments, each sphere of the plurality of spheres has adiameter in the range of 5 millimeter to 38 mm. In some embodiments, thesphere body has a diameter in the range of 3 millimeters to 34 mm. Insome embodiments, the plurality of hooks and the plurality of latcheshave an alternating pattern. In some embodiments, each hook of theplurality of hooks is separated from an adjacent latch of the pluralityof latches by a radial distance in the range of 10° to 45°. In someembodiments, each hook of the plurality of hooks has a length and thesphere body has a diameter, such that the ratio of the length to thediameter is in the range of 0.1 to 3.5. In some embodiments, each latchof the plurality of latches has a length and the sphere body has adiameter, such that the ratio of the length to the diameter is in therange of 0.1 to 3.5.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a 2-D schematic diagram of a sphere having hooks and latchesfor a lost circulation material in accordance with an embodiment of thepresent disclosure;

FIG. 2 is a 2-D schematic diagram of a structure (for example, a bridgeof plug) formed by the spheres of FIG. 1 via engagement between thehooks and latches in accordance with an embodiment of the disclosure;and

FIG. 3 is a block diagram of a process for the use of a hook and latchsphere lost circulation material (LCM) in accordance with an embodimentof the disclosure.

DETAILED DESCRIPTION

The present disclosure will be described more fully with reference tothe accompanying drawings, which illustrate embodiments of thedisclosure. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the illustratedembodiments. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art.

Embodiments of the disclosure include a lost circulation material (LCM)that includes spheres having radially distributed hooks and latches tofacilitate engagement (such as interlocking) of the spheres to create aflow barrier in a lost circulation zone. The LCM may be referred to inthe disclosure as a “hook and latch sphere LCM.” In some embodiments,the spheres may form plugs in channels, fractures, gaps, and otheropenings in a lost circulation zone. In some embodiments, the spheresmay form a bridge on which other LCMs may accumulate to seal and plugchannels, fractures, gaps, and other openings in a lost circulationzone. In some embodiments, the hook and latch sphere LCM may be used toprevent seepage-type lost circulation (for example, lost circulationzones having openings of less than 1 millimeter (mm) in size) tosevere-type lost circulation (for example, lost circulation zones havingopenings up to 114 mm in size).

FIG. 1 is a two-dimensional (2-D) schematic diagram of a sphere 100having a sphere body 102 and radially distributed hooks 104 and latches106 extending from the surface 108 of the body 102 in accordance with anembodiment of the present disclosure. As shown in FIG. 1, the hooks 104and latches 106 may be distributed in equally spaced radial directionsaround the circumference of the sphere body 102. In some embodiments,the hooks 104 and latches 106 may be in an alternating pattern. Thesphere body 102 may have a diameter 110 in the range of 3 millimeters(mm) to 34 mm. The diameter of the sphere 100 with the radiallydistributed hooks 104 and latches 106 may be in the range of 5 mm to 38mm.

Each hook 104 protrudes from the surface 108 of the sphere 100. The hook104 may have a length 116 in the range of 4 mm to 10 mm. In theembodiment shown in FIG. 1, each hook 104 includes a first hook arm 112and a second hook arm 114 in a symmetrical configuration. In someembodiments, each hook arm 112 and 114 may have a degree of curvature inthe range of 15° to 45°. In other embodiments, the hook 104 may havethree hook arms or four hook arms.

Each latch 106 may define an aperture 118 configured to receive an armof a hook 104. The aperture 118 may be closed at each end, that is, theend nearest the surface 108 and the end farthest from the surface 108.In some embodiments, each aperture 118 may be generally oval-shaped,circular-shaped, or may form other shapes. In some embodiments, thewidth of the aperture 118 is proportional to the length of the latch106. For example, each aperture 118 may have an aperture width to latchlength ratio in the range of 1:0.25 to 1:2. In some embodiments, theaperture width to latch length ratio is 1:1. Each latch 104 may have alength 120 in the range of 4 mm to 10 mm.

The hooks 104 and latches 106 are distributed radially around thecircumference of the sphere body 102 in equal directions. Each hook 104and latch 106 may have a radial separation in the range of 10° for 45°.For example, for embodiments having an alternating pattern, each hook104 may be separated from an adjacent latch 106 by a radial distance inthe range of 10° for 45°. As will be appreciated, in some embodiments anincrease in the diameter of the sphere body 102 may include a decreasein the radial spacing of the hooks 104 and latches 106, and a decreasein the diameter of the sphere body 102 may include an increase in theradial spacing of the hooks 104 and latches 106.

The sphere 100 may define a hook and latch length to sphere diameterratio (referred to as “da/db” ratio). In some embodiments, the da/dbratio may in the range of 0.1 to 3.5. In some embodiments, the da/dbratio may vary based on the particular application or deploymenttechnique used with the LCM. For example, a greater da/db ratio may beused to enable formation of a bridge from the spheres, such thatadditional LCMs may be introduced into the lost circulation zone to formseals or plugs on the bridge. In another example, a lesser da/db ratiomay be used to enable formation of plugs from the spheres without theuse of another LCM.

In some embodiments, the diameter of the sphere 100 having the hooks 104and latches 106 may be selected based on the deployment technique usedto deploy the LCM downhole to a lost circulation zone. In someembodiments, the LCM having the spheres 100 may be deployed through adrill bit. In such embodiments, the sphere 100 may have a diameter inthe range of 5 mm to 8 mm. In some embodiments, an LCM having thespheres 100 may be deployed using a bypass system (that is, a systemthat enables bypassing the BHA to introduce the LCM into the wellbore);in such embodiments, the sphere 100 may have a diameter in the range of9 mm to 14 mm. In some embodiments, an LCM having the spheres 100 may bedeployed using an open ended drill pipe; in such embodiments, the sphere100 may have a diameter in the range of 15 mm to 38 mm.

The sphere 100 may be formed from various materials that have thermalstability and resiliency. As used in the disclosure, the term “thermalstability” refers to stability of the material under downhole conditions(for example, temperature and pressure) in a well such that the materialdoes not degrade or dissolve. As used in the disclosure, the term“resiliency” refers to a material that is capable of elasticdeformation. For example, the hooks 104 and latches 106 of the sphere100 may be of sufficient resiliency so that the hooks and latches do notbreak off from the sphere body 102 when the sphere 100 impacts formationrock in a lost circulation zone.

FIG. 2 is a 2-D schematic diagram of a structure 200 (for example, abridge of plug) formed by the spheres 100 via engagement between thehooks 104 and latches 106 in accordance with an embodiment of thedisclosure. In should be appreciated that although FIG. 2 is a 2-Ddepiction, the structure 200 formed by the spheres 100 is athree-dimensional (3-D) structure. As shown in FIG. 2 each arm of a hook104 may engage an aperture of a latch 106 when a sphere is in sufficientproximity to another sphere. For example, with regard to labeled spheres202 and 204, an arm of the hook 206 of sphere 202 may engage theaperture of latch 208 of adjacent sphere 204. In this manner, eachsphere 100 may engage an adjacent sphere to form the structure 200 viaengagement of a hook with a latch. Each sphere may engage with one, two,three, four, five six or more spheres to from the structure 200.Additionally, the spheres around the edges of the structure 200 may beavailable for engagement with additional spheres subsequently introducedinto the lost circulation zone.

The structure 200 depicted in FIG. 2 may act as a bridge, a plug, orboth. For example, in some embodiments, the structure 200 may provide abridge for additional LCMs introduced into the lost circulation zone toform a seal or plug on the bridge. Additionally, or alternatively, thestructure 200 may form a plug that reduces or prevents lost circulationin a lost circulation zone without the use of additional LCMs. In someembodiments, the spheres used for formation of a bridge may have agreater da/db ratio than the spheres used for formation of a plug.

In some embodiments, the sphere 100 may be a nonmetallic material, suchas a polymer (for example, a plastic). In some embodiments, the sphere100 is formed from a non-swellable material, such that the spheres arenon-swellable in the presence of hydrocarbons or water. The materialforming the sphere 100 may have a rigidity sufficient to enableengagement between a hook and latch under downhole conditions (such astemperature and pressure) without deformation that prevents suchengagement.

In some embodiments, the sphere 100 may be produced using additivemanufacturing (for example, 3-D printing). The sphere 100 may beproduced using known 3-D printing techniques, such as direct ink writing(DIW), inkjet printing fused deposited modeling, or stereolithography,or other techniques. The printable material (for example, an ink) mayinclude a nonmetallic composition having the thermal stability andresiliency mentioned in the disclosure.

In some embodiments, the sphere 100 may be produced using a mold to castshredded rubber and a binder into the sphere 100. In some embodiments,the shredded rubber is shredded rubber from scrap tires (for example,magnetically separated crumb rubber). In some embodiments, the binder ispolyurethane.

In some embodiments, the sphere 100 may be produced using a mold to casta heat-resistant plastic (for example, a thermosetting polymer) into thesphere 100. In such embodiments, the sphere 100 may be produced usingknown plastic molding techniques, such as injection molding, orcompression molding, or transfer molding, or other techniques.

FIG. 3 depicts a process 300 for using the hook and latch sphere LCM inaccordance with an embodiment of the disclosure. Initially, the size andda/db ratio of the spheres in the hook and latch sphere LCM may beselected (block 302). As discussed in the disclosure, the size and da/dbratio of the spheres may be based on the type of lost circulation andthe deployment technique used to introduce the spheres into the lostcirculation zone.

In some embodiments, an LCM having a plurality of the spheres may beadded to carrier fluid to create an altered carrier fluid having thehook and latch sphere LCM for introduction into a lost circulation zone(block 304). For example, in some embodiments, the plurality of spheresmay be added directly to a drilling fluid, such as a drilling mud, tocreate an altered drilling fluid having the hook and latch sphere LCM.For example, in some embodiments, the plurality of spheres may be addedto (for example, mixed with) an oil-based drilling mud or a water-baseddrilling mud. In some embodiments, the hook and latch sphere LCM may beadded at the mud pit of a mud system.

In some embodiments, the hook and latch sphere LCM may have aconcentration in the range of 10 pounds-per-barrel (ppb) to 40 ppb inthe carrier fluid. For example, at these concentrations, the carrierfluid may be pretreated to prevent or mitigate fluid loss. When losscirculation is encountered, the hook and latch sphere LCM may have aconcentration in the range from 40 ppb to 200 ppb. As will beappreciated, such concentrations may be dependent on the mechanism ofintroduction into the lost circulation zone. For example, aconcentration of about 40 ppb may be a concentration limit of a motor orother BHA. In another example, a concentration of about 200 ppb may beused with an open ended drill pipe.

The altered carrier fluid may then be introduced into a lost circulationzone (block 306). After addition of the hook and latch sphere LCM to acarrier fluid, the altered carrier fluid (for example, the altereddrilling fluid) may be circulated at a pump rate effective to positionthe carrier fluid into contact with a lost circulation zone in awellbore, such that the plurality of spheres alter the lost circulationzone (such as by forming a structure in paths, cracks, and fractures).In some embodiments, the hook and latch sphere LCM may be introduced tothe lost circulation zone through a drill bit. In some embodiments, thehook and latch sphere LCM may be introduced to the lost circulation zoneusing a bypass system. In some embodiments, the hook and latch sphereLCM may be introduced to the lost circulation zone using an open endeddrill pipe.

In some embodiments, the hook and latch LCM may be used to form plugs inpaths, cracks, and fractures in a formation in the lost circulation zone(block 308). In such embodiments, after introducing the hook and latchLCM into the lost circulation zone, drilling operations may resume witha reduced rate of lost circulation of the drilling fluid.

In some embodiments, the hook and latch LCM may be used to form bridgesin paths, cracks, and fractures in a formation in the lost circulationzone (block 310). In such embodiments, an additional LCM may beintroduced into the lost circulation zone (block 312), such as via analtered drilling fluid having the additional LCM. The additional LCM mayaccumulate on the bridges formed by the hook and latch LCM to seal orplug the lost circulation zone. After introducing the additional LCMinto the lost circulation zone, drilling operations may resume with areduced rate of lost circulation of the drilling fluid.

Ranges may be expressed in the disclosure as from about one particularvalue, to about another particular value, or both. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value, to the other particular value, or both, along withall combinations within said range.

Further modifications and alternative embodiments of various aspects ofthe disclosure will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the embodiments described inthe disclosure. It is to be understood that the forms shown anddescribed in the disclosure are to be taken as examples of embodiments.Elements and materials may be substituted for those illustrated anddescribed in the disclosure, parts and processes may be reversed oromitted, and certain features may be utilized independently, all aswould be apparent to one skilled in the art after having the benefit ofthis description. Changes may be made in the elements described in thedisclosure without departing from the spirit and scope of the disclosureas described in the following claims. Headings used in the disclosureare for organizational purposes only and are not meant to be used tolimit the scope of the description.

What is claimed is:
 1. A lost circulation material (LCM) composition,comprising: comprising plurality of spheres, each sphere comprising: asphere body; a plurality of hooks, each hook extending outward from asurface of the sphere body and comprising a first hook arm and a secondhook arm, the second hook arm extending in a direction opposite thefirst hook arm; and a plurality of latches, each latch extending outwardfrom the surface of the sphere body and comprising an aperture, whereina hook of a sphere of the plurality of spheres is configured to engage alatch of an adjacent sphere via insertion of a first hook arm or asecond hook arm through the aperture such that the plurality of spheresform a structure.
 2. The LCM composition of claim 1, wherein each sphereof the plurality of spheres has a diameter in the range of 5 millimeterto 38 mm.
 3. The LCM composition of claim 1, wherein the sphere body hasa diameter in the range of 3 millimeters to 34 mm.
 4. The LCMcomposition of claim 1, wherein the plurality of hooks and the pluralityof latches comprise an alternating pattern.
 5. The LCM composition ofclaim 4, wherein each hook of the plurality of hooks is separated froman adjacent latch of the plurality of latches by a radial distance inthe range of 10° to 45°.
 6. The LCM composition of claim 1, wherein eachhook of the plurality of hooks has a length and the sphere body has adiameter, wherein the ratio of the length to the diameter is in therange of 0.1 to 3.5.
 7. The LCM composition of claim 1, wherein eachlatch of the plurality of latches has a length and the sphere body has adiameter, wherein the ratio of the length to the diameter is in therange of 0.1 to 3.5.
 8. An altered drilling fluid, comprising: adrilling fluid; and a plurality of spheres, each sphere comprising: asphere body; a plurality of hooks, each hook extending outward from asurface of the sphere body and comprising a first hook arm and a secondhook arm, the second hook arm extending in a direction opposite thefirst hook arm; and a plurality of latches, each latch extending outwardfrom the surface of the sphere body and comprising an aperture, whereina hook of a sphere of the plurality of spheres is configured to engage alatch of an adjacent sphere via insertion of a first hook arm or asecond hook arm through the aperture such that the plurality of spheresform a structure.
 9. The altered drilling fluid of claim 8, wherein eachsphere of the plurality of spheres has a diameter in the range of 5millimeter to 38 mm.
 10. The altered drilling fluid of claim 8, whereinthe sphere body has a diameter in the range of 3 millimeters to 34 mm.11. The altered drilling fluid of claim 8, wherein the plurality ofhooks and the plurality of latches comprise an alternating pattern. 12.The altered drilling fluid of claim 11, wherein each hook of theplurality of hooks is separated from an adjacent latch of the pluralityof latches by a radial distance in the range of 10° to 45°.
 13. Thealtered drilling fluid of claim 8, wherein the drilling fluid comprisesan oil-based drilling mud or a water-based drilling mud.